Remove useless argument from UnpinBuffer()
The last caller of UnpinBuffer() that did not want to adjust
CurrentResourceOwner was removed in
2d115e4, and nothing has been
introduced in bufmgr.c to do the same thing since. This simplifies 10
code paths.
Author: Aleksander Alekseev
Reviewed-by: Nathan Bossart, Zhang Mingli, Bharath Rupireddy
Discussion: https://postgr.es/m/CAJ7c6TOmmFpb6ohurLhTC7hKNJWGzdwf8s4EAtAZxD48g-e6Jw@mail.gmail.com